A bone-chilling winter throughout the Northern Hemisphere does not refute global warming
By LI LI

As Arctic winds blow over North America, Europe and East Asia, many parts of north China have also been struggling through snowstorm after snowstorm during the coldest winter in decades.

The Beijing Municipal Government announced the closure of primary and middle schools on January 4, 2010, to ease the burden on transportation after the city recorded its heaviest daily snowfall in nearly six decades on January 2. Neighboring Tianjin Municipality was also forced to extend the three-day national New Year holiday to four days for students due to heavy snow. Beijing Capital International Airport reported a total of 690 delayed and 96 canceled flights on January 3 and 4.

Meanwhile, snowstorms also caused havoc on the railways. On January 2, more than 1,400 passengers traveling from Heilongjiang Province's Harbin to Baotou in Inner Mongolia Autonomous Region in north China were stranded in the extreme cold for 20 hours when their 15-carriage train was partially buried by snow. Passengers were forced to spend the night and most of the next day in their carriages before they were rescued at about 3 p.m. on January 3.

Another 12 trains were also stranded by the snow in Inner Mongolia, with thousands of passengers trapped and later rescued from temperatures as low as minus 34 degrees Celsius.

In northwest China, blizzards killed at least 20 people in Xinjiang Uygur Autonomous Region as of January 27 after freezing temperatures and record snowfalls battered northern parts of the region. Military helicopters were mobilized to transport people trapped by the snow that measured up to two meters thick in some areas.

In east China, the Bohai Sea, a semi-enclosed inland sea the size of South Carolina, experienced its worst freeze in four decades. About half of the waters were covered by ice as of January 23. Ice floes stranded ships, disrupted oil production and caused economic losses to marine farms where frozen surfaces blocked oxygen to fish.

El Niño abnormal

The sudden drop in temperature came as a surprise to people in north China as meteorologists had predicted in December 2009 that the region would see a warmer-than-average winter.

Ren Fumin, a senior research fellow from the National Climate Center under the China Meteorological Administration, told the China News Service on December 9 that the 2009-10 winter return of El Niño had been confirmed as above-average sea surface temperatures in the central and eastern Pacific had lasted for six months. Ren said El Niño typically brings in a warm winter for most parts of China and rich rainfall in the south, along with increasing droughts, floods and other extreme events in the country.

However, Ding Yihui, a National Climate Center researcher, said on January 18 that the ongoing El Niño was a typical, which made accurate weather forecasting particularly difficult. Ding said the center of oceanic warming should be near the coast of South America in a regular El Niño year, but this year's above-average sea surface temperatures in the region mean the center has stayed in the central Pacific. Ding said this unusual warming pattern has made this El Niño more like La Niña, which usually means a cold winter in China and heavy rainfall and snowfall in northern parts.

Ding said another main reason for the chilly weather in the Northern Hemisphere this winter is the Arctic Oscillation (AO), an atmospheric circulation pattern in which atmospheric pressure over the polar region varies in opposition to that over the Earth's mid-latitudes. What is notable this year is that the pattern of high pressure over the Arctic is the most pronounced it has been in decades. In most years over the past few decades, the opposite has been true—there has been lower-than-average pressure over the Arctic and high-than-average pressure over the mid-latitudes. The center of mid-latitudes in the Northern Hemisphere cuts through China's northeastern Heilongjiang and Jilin provinces, Inner Mongolia and Xinjiang.

To be continued............

LIFE AS USUAL: The temperature in Fuyun County, Xinjiang Uygur Autonomous Region, drops to a rare low of minus 45 degrees Celsius on January 20 (CHEN QIAO)

The pattern usually confines cold Arctic air largely to the polar region. But the unusual pattern this year, an extreme negative phase of AO, allows cold air to flow south from the Arctic and results in winter weather in Northern Europe, North America and East Asia. "The negative phase of AO has occurred many times in history, but it is unusual for high pressure to occupy the Arctic for such a long time this year," said Ding.

According to Wang Yongguang, a senior research fellow with the National Climate Center, polar air masses meet vapor while flowing across the ocean during the process of moving southward, which results in blizzards in China's northeastern provinces and eastern parts of the United States.

Wang Shaowu, a Peking University's Department of Atmospheric Sciences professor, said that scientists around the world still disagree over how long the negative phase of the AO could last. "There hasn't been a universally acknowledged prediction scheme," said Wang.

Warming world

Most Chinese scientists say that cold conditions around the Northern Hemisphere do not justify claims that global warming has ended.

Ding said although China's first snow is one month earlier than average and many places have recorded their coldest December ever, the year 2009 was actually China's fourth warmest year on record since 1951 as far as national temperatures are concerned. "Blizzards and extremely low temperatures in some places are extreme weather events, which cannot reverse global warming, a rise of average temperature around the world," Ding said.

Ren said China's average land temperature climbed by 0.81 degrees Celsius between 1905 and 2006, which is almost at the average global warming speed. He said the public should not think that global warming means that every place will be consistently warmer than the year before everywhere on Earth and that cold weather in some areas over the course of a single winter mean global warming is not happening. He said temperatures would continue to rise as long as the density of greenhouse gases in the atmosphere keeps increasing.

"In the context of global warming, there will be an obvious increase in extreme weather events," said Ding.

Ding explained that rising temperatures could accelerate the Earth's water cycle, which could boost ocean evaporation and increase the risks of rainstorms. Meanwhile, the increase in ground evaporation could lead to more droughts.

As for some scientists' belief that the bitter winter in the Northern Hemisphere is only the start of a global trend toward cooler weather for the next 20 or 30 years, Ding said there is not enough evidence to sustain a mini-ice-age theory. He said many complicated factors contribute to climate change, such as human, solar and volcanic activity and internal changes within the climate system, meaning that ignoring any single factor could undermine the accuracy of the forecast.

He said four factors—low solar radiation output, reflective sulfate aerosols generated by frequent volcanic eruptions, the declining positive phase of AO and temperature drops in the central equatorial Pacific—have increasingly weakened the global warming trend since 1998, the warmest year on record. But he also said despite those factors, the last decade was still the fifth warmest on record since 1851.

Ding predicts that the climate will continue to turn warmer after 1998 while the chances for extreme cold weather grow, along with the damage caused by the chill.

"In the past, the academy might have overrated the sensitivity of the climate system to greenhouse gas density in the atmosphere. We need to study further to understand the factors behind climate change," said Ren.

Chen Xianyao, a research fellow with the State Oceanic Administration, is about to launch his study on the links between climate and ocean change. He told Guangming Daily that he disagrees with the Intergovernmental Panel on Climate Change hypothesis that global warming is due mainly to human activities. He believes that global temperature vibrates in a cycle of 65 to 70 years and peaked over the past decade. "I know I am the minority with this view," said Chen.

But the Chinese Government is determined to protect the voices of non-mainstream scholars like Chen.

"While some people believe global warming is caused by human activities, other people insist that it results from cyclical trends in nature itself. We should keep an open attitude toward these debates,"

said Xie Zhenhua, Vice Minister of the National Development and Reform Commission, during an international environmental conference in New Delhi.

Chen Xianyao, a research fellow with the State Oceanic Administration, is about to launch his study on the links between climate and ocean change. He told Guangming Daily that he disagrees with the Intergovernmental Panel on Climate Change hypothesis that global warming is due mainly to human activities. He believes that global temperature vibrates in a cycle of 65 to 70 years and peaked over the past decade. "I know I am the minority with this view," said Chen.

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To Chen Xianyao: You are wrong in your thinking. As sure as I can be, you are certainly not in the minority with your views in the world.

The discussion here is with reference in time to the contents of this principal thread by climate scientists from China's National Climate Center and the State Oceanic Administration. The topic under discussion was the extreme snow fall and cold during the last winter. So what it is summer now?